Page 16 - THREADING CATALOG

INTRODUCTION
INTRODUCTION Recommended Tolerance Classes for Internal Threading short Position H long

Position G
Tolerance Class
normal
short
long
normal
Fine
---
---
---
6H
5H
4H
5G
Medium
7G
6G
---
Coarse
8G
---
8H
7H
7G
Recommended Tolerance Classes for External Threading 5H 6H 7H
Position E Position F Position G Position H
Tolerance Class
short normal long short normal long short normal long short normal long
Fine --- --- --- --- --- --- --- 4g 5g4g 3h4h 4h 5h4h
Medium --- 6e 7e6e --- 6f --- 5g6g 6g 7g6g 5h6h 6h 7h6h
Coarse --- 8e 9e8e --- --- --- --- 8g 9g8g --- --- ---
When
rd
1 Choice 2 Choice 3 Choice
nd
st
** bold - most common
There are several options for thread description with accuracy class according to the ISO standard:
Internal Threading
Major Diameter x Pitch - Tolerance Class for Pitch Diameter Tolerance Class for Minor Diameter
M8X1.25 – 5H 6H
Major Diameter - Tolerance Class for Pitch and Minor Diameter
M8 – 6H
External Threading
Major Diameter x Pitch - Tolerance Class for Pitch Diameter Tolerance Class for Major Diameter
M8X1.25 – 5g 6g

Major Diameter - Tolerance Class for Pitch and Major Diameter
M8 – 6g

ISCAR
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